I want to tell you about the most embarrassing 45 minutes of my developer career. I had been practicing LeetCode for three months. Easy problems, done. Most mediums, done. I felt ready. The interviewer shared their screen and showed me this: x = [ 1 , 2 , 3 , 4 , 5 ] y = x y += [ 6 , 7 ] print ( x ) print ( y ) "What does this print?" I panicked. Not because the code was complex. Because I had never practiced r...